import java.util.Scanner;

public class Text5 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[][] arr = new int[n][2*n-1];
        arr[0][n-1]=1;
        for (int i = 1;i<n;i++){
            for (int j=0;j<2*n-1;j++){
                if (j!=0&&j!=2*n-2){
                    arr[i][j] = arr[i - 1][j] + arr[i - 1][j - 1] + arr[i - 1][j + 1];
                } else if (j==0){
                    arr[i][j] = arr[i - 1][j]  + arr[i - 1][j + 1];
                } else if (j==2*n-2){
                    arr[i][j] = arr[i - 1][j]  + arr[i - 1][j - 1];
                }
            }
        }

        for (int i=0;i<2*n-1;i++){
            if (arr[n-1][i]%2==0){
                System.out.println(i+1);
                return ;
            }
        }

        System.out.println(-1);
    }
}
